보통 상대방이 병에 걸렸다, 아프다 하면..

That's too bad.

I'm sorry to hear that.

이라 많이 쓰는데 더 좋은 표현들이 있으니 익혀 두시기 바랍니다.

I was shocked to learn that you have been sick.

I was much surprised to hear of your illness.

(아프다는 소식듣고 매우 놀랐어)

Learn은 여기서 '배우다'가 아닌 '알다'의 뜻으로 쓰였죠.

I'm sorry to hear that you've been sick.

It's with great sorrow that I heard you have been ill.

(너가 앓고 있다고 해서 너무 마음이 아파)

Take good care of yourself!

(몸조리 잘해!)

I do hope you will take good care of yourself and recover soon.

(몸조리 잘하고 곧 회복되길 간절히 희망한다)